The read/write head of a magnetic tape recorder is particularly sensitive to contamination, since dirt in the form of abraded tape or metal particles can lead to read and write errors and can even result in storage failures or even loss of data. Since magnetic tape recorders of this kind are generally used for filing purposes, such failures are irreparable.
A problem with the cleaning of read/write heads of magnetic tape recorders consists in that the surfaces of these heads facing the magnetic tape are not level but slightly staggered. Furthermore, the read/write head can be swivelled away with some magnetic tape recorders in order to facilitate tape removal and to avoid damage to the recording surfaces or the tape, respectively, when unloading the tape cassette.
It should be noted after all that the read/write head of a magnetic tape recorder is usually cleaned every four to six operating hours.
A generic cleaning cassette disclosed by the prior art incorporates a tape guided within the cassette which is manually pulled past the read/write head to be cleaned after the cassette has been inserted, whereby particularly magnetic particles are abraded and carried away from the read/write head. Quite apart from the fact that such a cleaning cassette is relatively expensive it should be noted that the cleaning tape cannot be wider than the data medium of a normal recording cassette. This means that contaminations which are found beyond the lateral boundaries of the active strip of the read/write head are not removed but are rather drawn by magnetic attraction on to the recording strip of the head after the cleaning process. But even the cleaning effect on the recording strip (active strip) itself is insufficient because, as stated above, this strip on the read/write head is not level but has some degree of uneveness designed in, whereas a cleaning tape can only make contact with even surfaces owing to its shape. A magnetic tape data medium is generally driven by rollers which act upon the tape reels but cause significant contamination resulting from debris. This contamination being primarily found at the sides of the active strip cannot be removed by a cleaning tape.
Apart from the cleaning by means of a cleaning cassette, other cleaning methods are known, e.g. by means of a brush, which must be applied in addition to the use of a cleaning cassette in order to clean the areas at the sides of the active strip of the read/write head and to account for the fact that a cleaning cassette can only effect dry cleaning. Particularly in the case of additional contaminations by debris and also to reduce frictional magnetism, moist or wet cleaning using solvents becomes necessary. Moist or wet cleaning with a brush involves the risk that the dirt is only dislocated to inaccessible places or that the magnetic tape recorder and here especially the read/write head is damaged during the cleaning process. There can even result irreparable damage if recording errors or failures occur that remain undetected and will lead to gaps in the filed documents.